Temporary vascular scaffold and scoring device

ABSTRACT

Devices and methods for treating a target site in a body lumen are provided. A medical device includes a stent-like structure including a plurality of scoring and non-scoring filaments interwoven with one another. Generally, the stent-like structure will have more non-scoring filaments than scoring filaments to provide greater structural support and to focus the scoring forces on only a few select areas. The stent-like structure is expanded within the target site to score the target site and to provide temporary structural support while the target site is infused with a therapeutic agent. Such therapeutic agent infusion occurs with the use of a drug eluting or drug coated balloon disposed within the stent-like structure or by occluding the target site and introducing a drug into the occluded target site to sit for a period of time.

CROSS-REFERENCE TO OTHER APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/426,290, filed May 30, 2019, which is continuation of U.S. patentapplication Ser. No. 16/156,661, filed Oct. 10, 2018, now abandoned,which is a continuation of U.S. patent application Ser. No. 15/005,848,filed Jan. 25, 2016, now abandoned, which is a continuation of U.S.patent application Ser. No. 14/080,917, filed Nov. 15, 2013, now U.S.Pat. No. 9,277,935, which claims the benefit of U.S. ProvisionalApplication No. 61/796,596, filed Nov. 15, 2012, which applications areincorporated herein by reference.

This application is related to co-owned U.S. patent application Ser. No.12/813,339, now U.S. Pat. No. 8,740,961, filed on Jun. 10, 2010, whichclaims the benefit of U.S. Provisional Application No. 61/274,165, filedon Aug. 13, 2009 and U.S. Provisional Application No. 61/277,154, filedon Sep. 21, 2009, the disclosures of which are incorporated byreference.

This application is also related to co-owned U.S. Pat. No. 6,238,412,the disclosure of which is incorporated by reference.

BACKGROUND OF THE INVENTION

Balloon angioplasty has been a popular method of treating vascularocclusions since 1976. With plain old balloon angioplasty (POBA), thereexists a significant subset of patients who have immediate suboptimalresults related to the trauma to the vessel including dissection of thevessel, incomplete plaque compression, poor lumen gain, and acuteelastic recoil of the vessel, amongst others. Because of thesesuboptimal immediate results, other means to treat vascular stenosiswere developed. Intravascular stents are widely utilized, addressing theacute problems of angioplasty and reducing the restenosis rates from50-60% for POBA to 30-35% for these bare metal stents (BMS).

Because the restenosis rates of BMS are usually unacceptable, drugeluting stents (DES) are used to inhibit restenosis. These devicesreduce the restenosis rate to around 20% and lower in the coronarycirculation. However, DES are extremely expensive and can lead tothrombosis, which can prove fatal. In addition, DES are not particularlyeffective in the peripheral circulation. The expense of drug elutingstents at over $3000 each dramatically increases the overall cost ofhealthcare in the U.S. Finally, not only are the stents are costly, butexpensive and potentially harmful drugs are routinely used for at leasta year after stent implantation.

Restenosis is an Achilles heel of all vascular intervention, fromangioplasty to stenting and even surgery. Various drugs can preventrestenosis. A primary question is how best to deliver the drugs in themost cost effective manner available while producing good patientoutcomes and preventing complications.

Because of variable plaque morphology and composition, stresses providedby conventional POBA can be unpredictable, and frequently high pressureballoon inflations are often needed to successfully provide enoughstress to crack the plaque. When the plaque does compress at highpressures, the balloon will often very rapidly expand to its fulldimension in a noticeable pop (tenths of a second), very rapidlyexpanding the vessel wall often rupturing the smooth muscle cells.Dissection frequently occurs, as does irreparable injury to the smoothmuscle cells which do not have the chance to gradually stretch anddeform to maintain their integrity.

Therefore, methods and devices that lower the pressure at which theplaque will fracture will often produce a slower and more gradualstretching of the arterial wall. This slower stretching can diminish thedegree of trauma to the vessel.

A wire or wires along the outside of an angioplasty balloon, sometimescalled buddy wires, can produce focal areas of stresses along the wiresthat were approximately 120 times that of a conventional balloonsurface, and the stress patterns from the external wire extends into theplaque rather than being concentrated on the surface as with aconventional balloon. The stress patterns are typically less dependenton the morphology and composition of the plaque than with conventionalballoons. In other words, the stresses can be more predictable andconcentrated and require lower balloon pressures to compress the plaque.Clinical studies have confirmed that when compared to conventional POBAcatheters, the buddy wire technique compressed the plaque at lowerballoon pressures, caused fewer dissections, had less elastic recoil,and had more lumen gain, as well as a trend toward lower restenosisrate.

More recently, cutting and scoring balloons have been introducedextending these concepts. One such balloon uses several razor typeblades along the balloon margins. Scoring balloons may utilize several0.005 to 0.007 inch struts placed over a balloon. Both balloon types arecommercially successful. They are typically used in treating complexlesions or in plaque modification. The scoring balloon has been shown toachieve 50% more lumen gain than POBA when utilized as predilatationbefore stent implantation. This procedure can significantly reduce thenumber of dissections when compared to POBA. The scoring balloon alsohas been shown to not slip off of the lesion, which is a problem withPOBA. The scoring balloon can also be more effective in soft, fibrous,and calcified plaques than POBA and has been recommended as a strategyof plaque modification in treating complex lesions. The use of thescoring balloon has thus resulted in very low incidences of inadvertentor unplanned stenting, commonly referred to as bail out stenting.

Prolonged inflation times improve the immediate results of POBA withfewer dissections, fewer further interventions such as stenting, andless restenosis. On the other hand, other studies did not showimprovement in long term results with prolonged inflation times,possibly because their prolonged inflations were the result of treatingdissections. Currently, no studies that evaluate both plaquemodification and prolonged inflation times have been conducted orpublished.

While these mechanical strategies have resulted in measurableimprovement in the acute complications of POBA, a promising advancementin POBA has been the advent of drug eluting balloons (DEB's). A DEB is aPOBA balloon coated with an antiproliferative drug, such as paclitaxel.The drug is delivered during the rather short balloon inflation and hasbeen shown to be present in smooth muscle cells up to six days later.The drug from a DEB covers essentially 100% of the plaque/vessel wallvs. only 15-20% with drug eluting stents. Compared to DES in treatingcoronary in-stent restenosis, a DEB seems preferable. In the THUNDERtrial (sponsored by University Hospital Tuebingen, Tuebingen, Germany,reported in The New England Journal of Medicine, volume 358:689-699,Feb. 14, 2008, Number 7), a DEB was compared to POBA in the peripheralvasculature. DEB was very effective, and at 2 years, the target lesionrevascularization rate was only 15% with the DEB vs. 59% with POBA. Mostexperts in the field expect the general usage results of DEB's incoronary circulation to be in the range of drug eluting stents, i.e., arestenosis rate of around 20% or so. This rate leaves considerable roomfor improvement.

Therefore, both mechanical and pharmacological strategies have shownadvantages in treating vascular lesions with balloon angioplasty. Themechanical strategies effectively address the acute or immediateproblems by causing less injury to the vessel and the pharmacologicalstrategy of drug eluting balloons significantly diminish restenosis.

Moreover, recent experiments have demonstrated that infusion ofpaclitaxel, an antiproliferative drug, directly into the artery may bejust as effective as drug eluting balloons or drug eluting stents. Thisis usually done by employing a catheter specifically designed forinfusion of a drug over the site of the angioplasty or stent placementafter the angioplasty and/or stent placement. This type of catheterusually has two balloons, one proximal and one distal. The drug or otheragent is infused between the two in a closed system, drug infusionperformed after the angioplasty, stent placement or other therapeuticprocedure. This typically requires removal of the angioplasty balloon orstent delivery catheter, which is utilized prior to the drug delivery,and subsequent placement of a separate device to deliver the drug. Thiscan be problematic not only because of the cost of the extra device, butalso platelets adhere over the fissures in the plaque and about thesmall areas of injury in the arterial wall while the exchange is takingplace, preventing some of the drug from being delivered to the wallwhere it is needed. Additionally, by just infusing a drug into a spacethat has been previously dilated, there is very little pressure forcingthe drug into the wall. Subsequent to the therapeutic procedure and thedrug delivery steps, the drug is then released downstream.

In U.S. Pat. No. 5,059,178, Ya et al. describe a device with adownstream balloon catheter blocking element and an upstream suctioncatheter with a balloon blocking element for the removal of thrombusfrom a blood vessel. The device is utilized to dissolve the thrombus byinjecting a dissolving agent into the space between the two balloons andthen withdraw the dissolved thrombus from the body through upstreamsuction catheter. Any subsequent intervention or therapy (angioplasty,stent placement, and the like) are performed after the removal of thedissolved thrombus.

In U.S. Pat. No. 6,022,366, Zadno-Azizi et al. describe another doubleballoon device similar to one described by Ya above but is directedtoward embolic containment. This device is actually a three catheterirrigation/aspiration system and also has an innermost downstreamballoon blocking or occluding element and an outermost upstream balloonocclusion catheter with an intermediate catheter between the two. Theirrigation/aspiration of debris and emboli occurs by use of the outerpathway between the upstream balloon occlusion catheter and theintermediate catheter, and by the use of the inner pathway between theintermediate catheter and the innermost downstream balloon blockingelement. The use of three catheters tends to reduce the cross-sectionalsize of the pathway available for aspiration of material.

In U.S. Pat. No. 5,449,372, Schmalz et al. describe a temporary stentthat can be used for support after dilatation of the lesion.

In U.S. Pat. Nos. 6,450,989 and 7,011,654, William R. Dubrul and Idescribe a dilating and support apparatus with disease inhibitors andmethods of use.

In U.S. Pat. No. 7,232,432, William R. Dubrul and I describe a porousbraided structure for angioplasty and drug delivery.

The following U.S. Patents and Publications may also be of interest:U.S. Pat. Nos. 8,454,636, 7,494,497, 7,279,002, 6,808,531, 5,797,935,and 5,766,203, and U.S. Publication Nos. 2013/0041391, 2011/0082483, and2005/0080478.

BRIEF SUMMARY OF THE INVENTION

To address the problem of how best to deliver the drugs in the most costeffective manner available while producing good patient outcomes andpreventing complications, the medical device industry has essentiallyfocused on developing methods and devices that inhibit the vascularresponse to the injury (restenosis), as opposed to developing a devicethat causes less injury, and hence less restenosis. One aspect of thepresent invention is directed to a device and method that both causesless injury to the vasculature by the use of dilatation of a specializedbraid over a balloon causing less dissection and more even plaquedisruption at lower pressures and introduces drug deep within the vesselwall; this latter act is accomplished by using proximal and distaloccluders, injecting an agent, such as an anti-proliferative drug, intothe region between the occluders, and performing an intervention, suchas balloon angioplasty, while the occluders and injected agent remain inplace. Another aspect of the invention also helps to maintain pressureupon the vessel wall similar to prolonged balloon inflation by using abraided, stent like structure as a temporary or transient stent. Thusless initial injury and less elastic recoil should result in lessrestenosis, and delivering a drug will further reduce or prevent therestenosis.

It is the immediate result of an intervention (the immediate lumendiameter and the immediate residual percent stenosis) that typicallydetermines the late outcome after coronary or other vascularintervention. Many embodiments of the present invention are designed toimprove these two factors. An optimal outcome in percutaneousinterventions depend upon: 1) obtaining an excellent acute angiographicresults with less dissection and elastic recoil, 2) avoiding damage tothe distal vascular bed (as with atherectomy), and 3) reducing smoothmuscle cell proliferation with pharmacological intervention. Aspects ofthe present invention address all three areas.

Many embodiments of the present invention are directed to a method oftreating a target site within a vascular channel of the body using acatheter assembly, the catheter assembly comprising a proximal occluderand a distal occluder. The method includes the following steps. Theproximal occluder is positioned in a vascular channel-occluding statewithin the vascular channel at a first position proximal of a targetsite thereby occluding the vascular channel at the first position. Thedistal occluder is positioned in a vascular channel-occluding statewithin the vascular channel at a second position distal of a target sitethereby occluding the vascular channel at the second position andthereby defining a region between the distal and proximal occluders. Anagent is injected into the region. An intervention is performed at thetarget site while the distal and proximal occluders are in theirvascular channel-occluding states and the agent is in the region. Thecatheter assembly is removed from the vascular channel.

In some embodiments, the intervention performing step comprisesexpanding an expansion device, such as a balloon and a temporary stentstructure covering the balloon, against an inner wall of the vascularchannel. In some embodiments, the balloon is collapsed leaving the stentstructure expanded against the inner wall for a period of time, and thecollapsed balloon and the collapsed stent structure are removed from thevascular channel during the stent structure removing step.

In many embodiments, the balloon stent assembly comprises a catheterassembly having a proximal portion and a distal portion. The catheterassembly may comprise first and second elongate members. A temporarystent may have proximal and distal ends; the proximal end being securedto a first position along the first elongate member and the distal endbeing secured to a second position along the second elongate member. Thetemporary stent may be placeable in a contracted state by movement ofthe first and second positions away from one another. The assembly mayalso include an inflatable balloon mounted to the distal portion of thecatheter assembly at a location surrounded by the temporary stent. Theballoon may be placeable in an inflated state, thereby placing thetemporary stent in an expanded state, and in a collapsed state. Thetemporary stent can be free to remain in the expanded state when theballoon moves to the collapsed state.

By utilizing the balloon to expand the temporary stent, not only thepressure of the balloon is brought to bear on the obstruction, but itsactions can be enhanced by the overlying temporary stent structure. Thewires of the temporary stent may provide areas of focal force on theplaque that will allow the plaque or obstruction to be dilated with lesspressure creating a controlled expansion compared to the uncontrolledrupture and dissections frequently seen with POBA. There may be a moregradual stretching and more gradual deforming of the smooth musclecells, and they may have an opportunity to accommodate this stretchingand maintain their integrity rather than being irreparably injured as isfrequently the case with POBA.

Therefore, the balloon can serve two distinct functions: 1) it candilate the plaque or obstruction (and in a more consistent mannerbecause of the overlying temporary stent structure), and 2) it candilate the temporary stent more effectively, with more force, and withmore lumen gain than could be achieved by dilating the temporary stentstructure without the assistance of the balloon.

Therefore, together the balloon along with the temporary stent may beable to effectively dilate and then support the dilated vesselsubsequent to the dilatation.

In some embodiments, the first elongate member comprises an outer,actuator sleeve and the second elongate member comprises an inner,balloon catheter shaft to which the balloon is mounted. In someembodiments, the temporary stent comprises a porous braided stentstructure.

Treating advanced vascular disease is one of the largest health careexpenses born by society. There are projected to be one millionnon-coronary angioplasties and 900,000 stand alone coronaryangioplasties in 2012. (Millennium Research Group, 2009. American HeartAssociation, Heart Disease and Stroke Statistics, 2009 Update at aGlance.) Many simpler, less expensive interventional methods, such asPOBA, are frequently not effective, necessitating the use of morecomplex and expensive alternatives, such as stenting and surgery, whichcost billions of dollars each year.

The use of the present invention is expected to improve on the resultsof POBA and reduce or avoid the need for stenting and/or surgery, bycausing less vascular injury initially, preventing elastic recoil thatfrequently demands stenting, and preventing restenosis by simultaneouslyadministering a non-proliferative agent. Procedures conducted accordingto many embodiments of the present invention are expected to cost onlymarginally more than POBA.

A rough calculation shows that the use of many embodiments of thepresent invention could result in large cost savings of over $1 billionper year as approximately 1.9 million peripheral angioplasties and standalone coronary angioplasties (not associated with stent implantation)will be performed in 2012. (Millennium Research Group, 2009. AmericanHeart Association, Heart Disease and Stroke Statistics, 2009 Update at aGlance.) By replacing POBA with the many embodiments of the presentinvention in all cases, and diminishing the re-intervention rate from40% of 1.9 million patients (760,000 patients) to 10% (190,000patients), approximately 570,000 patients would be sparedre-intervention. At a Medicare reimbursement cost of $5850/procedure,there would be savings of $3.33 billion/year. Currently, such restenoticlesions are usually treated with stents, surgery, or other more costlymethods. On average, these added procedures add a cost of about $2,000for each procedure. If the $2000 is added to each re-intervention in 80%of these cases, then the savings are increased by $912 million (570,000procedures×80%×$2000=$912 MM), for a total possible savings of $4.24billion per year. A market penetration of 25% would result in yearlycost savings of over $1 billion per year, not even considering theexpected diminished incidence of costly “bail out” or unanticipatedstenting when using the present invention.

An aspect of the present invention provides a medical device fortreating a target site in a body lumen. Often, the target site will be aregion of a blood vessel occluded with plaque. The medical device maycomprise a stent-like structure which may comprise a plurality ofscoring filaments or elements and a plurality of non-scoring filamentsor elements. The scoring filaments and the non-scoring filaments may beinterwoven with one another. Alternatively or in combination, at leastsome of the scoring and non-scoring filaments may not be interwoven withone another. For example, the filaments may be struts of a laser-cutscaffold. The stent-like structure may typically comprise a tubular meshbraid. The plurality of non-scoring filaments may be configured toradially support the body lumen after the stent-like structure has beenexpanded therein. The stent-like structure may comprise more non-scoringfilaments than scoring filaments. By providing more non-scoringfilaments or elements than scoring filaments or elements, greaterstructural strength and improved scoring by the stent-like structure canbe provided. Scoring of a lesion or occlusion in the body lumen, forexample, may depend on providing a focal force at one or several areasupon and within the plaque. If too many filaments are scoring filaments,this focal force would be diluted or divided over all of the filamentsand none may be dominant in directing force into the plaque to cause theplaque to fracture beneath the scoring filaments. Thus, only a limitednumber of scoring filaments or elements may be needed to produce thedesired results of a few areas of focal fracturing of plaque present inthe body lumen such as a blood vessel.

The stent-like structure typically has an expanded configuration and acollapsed configuration. The stent-like structure in the expandedconfiguration may be collapsible into the collapsed configuration. Thestent-like structure in the expandable configuration can be collapsedinto the collapsed configuration by axially shortening the stent-likestructure.

One or more of the plurality of scoring filaments or the plurality ofnon-scoring filaments may be non-axial. For example, one or more of theplurality of scoring filaments or the plurality of non-scoring filamentsmay be helically wound over a longitudinal axis of the stent-likestructure. Also, one or more of the plurality of scoring filaments orthe plurality of non-scoring filaments may be helically wound in thesame direction.

Each scoring filament may have one or more of a pointed, triangular, orrectangular shape. Each non-scoring filament may have one or more of aflat, rounded, rectangular, or cylindrical shape. At least one scoringfilament may comprise a plurality of notches for receiving at least onenon-scoring filament as the non-scoring filament(s) crosses through thescoring filament(s). The plurality of notches may be distributed (e.g.,evenly distributed) over a length of the at least one scoring filament.

The medical device may further comprise an expandable element. Thestent-like structure may be disposed over the expandable element. Theexpandable element may be expandable to urge the stent-like structureradially outward against an inner wall of the body lumen. The expandableelement may comprise an inflatable balloon. The expandable element maybe independently collapsible from the stent-like structure. Theexpandable element may comprise an outer surface coated with atherapeutic agent or substance. The expandable element may comprise oneor more pores for releasing a therapeutic agent or substance.

The medical device may further comprise a catheter shaft, and theexpandable element may be disposed over the catheter shaft. The medicaldevice may further comprise an expandable proximal occluder disposedover the catheter shaft proximal of the expandable element and thestent-like structure. The medical device may further comprise anexpandable distal occluder. The distal occluder may be advancablethrough an inner lumen of the catheter shaft to be positioned distal ofthe expandable element and the stent-like structure. The distal occludermay non-inflatable, for example, such as a malecot.

Another aspect of the present invention provides a medical device fortreating a target site in a body lumen. Often, the target site will be aregion of a blood vessel occluded with plaque. The medical device maycomprise a stent-like structure which may comprise a plurality ofscoring filaments and a plurality of non-scoring filaments. The scoringfilaments and the non-scoring filaments may be interwoven with oneanother. Alternatively or in combination, at least some of the scoringand non-scoring filaments may not be interwoven with one another. Atleast one scoring filament may comprise a plurality of notches forreceiving at least one non-scoring filament as the non-scoringfilament(s) crosses through the scoring filament(s). The plurality ofnotches may be distributed (e.g., evenly distributed) over a length ofthe at least one scoring filament.

Another aspect of the present invention provides methods of treating atarget region in a body lumen. Often, the target site will be a regionof a blood vessel occluded with plaque. A catheter assembly may bepositioned at or near a target region in the body lumen. An expandableelement of the catheter assembly may be expanded (i) to expand astent-like structure disposed over the expandable element and (ii) tourge both the expandable element and the stent-like structure against aninner wall of the target region. In some embodiments, the inner wall mayalso be scored with one or more of the stent-like structure or theexpandable element. A therapeutic agent may be released from an outersurface of the expandable element for infusion into the inner wall.Alternatively or in combination, a therapeutic agent may be releasedfrom one or more pores of the expandable element for infusion into theinner wall. In many embodiments, the target region may be isolated byexpanding at least two occluders—a distal occluder distal of the targetregion and a proximal occluder proximal of the target region. Theexpandable element may be collapsed to leave the stent-like structureexpanded against and radially supporting the inner wall. The stent-likestructure may be left expanded against the inner wall for a period oftime to one or more of (i) inhibit elastic recoil of the inner wall,(ii) allow the therapeutic agent to infuse into the inner wall, and(iii) inhibit or minimize flow limiting dissections. Finally, thestent-like structure may be collapsed after the period of time and thecatheter assembly may then be from the target region.

Other features, aspects and advantages of the present invention can beseen on review the figures the detailed description, and the claimswhich follow.

INCORPORATION BY REFERENCE

All publications, patents, and patent applications mentioned in thisspecification are herein incorporated by reference to the same extent asif each individual publication, patent, or patent application wasspecifically and individually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the present invention are set forth withparticularity in the appended claims. A better understanding of thefeatures and advantages of the present invention will be obtained byreference to the following detailed description that sets forthillustrative embodiments, in which the principles of the invention areutilized, and the accompanying drawings of which:

FIGS. 1-10 show structures as shown in co-owned U.S. Pat. No. 6,238,412.

FIG. 1 is a mechanical schematic showing the device fully deployed in aDacron® graft used in hemodialysis. FIG. 1 shows the blocking element atthe distal end of the catheter in its radially expanded state and theocclusion engaging element at the distal end of the support wire in itsradially expanded state. The proximal blocking element may take avariety of shapes as would be required for the particular application.The preferred shape is likely to be a funnel shape where the largerdiameter is distal to the lesser diameter that is proximal on theelement. This funnel shape can allow the obstruction to be more easilyaccepted into the catheter due to the pull/push of the engaging element,aspiration or both.

FIG. 2 is a side view of the distal portion of the support wire with abraided occlusion engaging element in its radial compressed state. FIG.2 shows the state where the support wire and engaging element can beinserted through the occlusion that is to be removed.

FIG. 3 shows the FIG. 2 braided occlusion engaging element in itsradially expanded state, which is the state shown in FIG. 1.

FIG. 4 is a perspective view, in partial cross-section, showing themulti-wing malecot type blocking element at the distal end of thecatheter in its radially expanded state, which is the state shown inFIG. 1. It should be noted that the scale of the FIG. 4 catheter is muchreduced compared to the scale of the occlusion removal wire and braidedelement shown in FIGS. 2 and 3.

FIG. 5 is a side view, in partial cross-section, showing the catheterand dilator with a ferrule at the distal tip of the guide wire in apassageway having an occlusion that is to be removed.

FIG. 6 is a side view, in partial cross-section, showing the next stepin which the dilator is being removed thereby causing the malecot typeblocking mechanism to become expanded by virtue of pressure against thedistal end of the catheter tip of the dilator.

FIG. 7 is a side view, in partial cross-section, showing the next stepin which the support wire together with the braided occlusion removalelement in its radially compressed state (the state shown in FIG. 2) isinserted through the catheter and through the occlusion to be removed.

FIG. 8 is a side view, in partial cross-section, showing the next stepin which the braided occlusion removal element has been expanded and isbeing pulled in a proximal direction thereby forcing the occlusion intothe catheter for removal with or without aspiration.

FIG. 9 is a perspective view, in partial cross-section, showing themulti-wing malecot type blocking element at the distal end of thecatheter in its radially expanded state.

FIG. 10 is a side view, in partial cross-section, showing the shape ofthe expansion resulting from the malecot type blocking element shown inFIG. 9.

FIGS. 11-20 illustrate exemplary devices and procedures in accordancewith many embodiments of the present invention.

FIG. 11 is a side view, in partial cross-sectional, view of a catheterassembly with the balloon expanded at a target site, in accordance withmany embodiments.

FIGS. 12-17 are side views, in partial cross-section, showing thevarious steps in the use of the catheter assembly of FIG. 11.

FIGS. 18-20 show side views of another embodiment of a catheter assemblyin which a removable, expandable braid, acting as a stent likestructure, is positioned over the balloon, with the balloon and thebraided stent-like structure both in expanded states in FIG. 18, withthe braided stent like structure in an expanded state and the balloon ina collapsed state in FIG. 19, and the balloon and a braided stent likestructure both an collapsed states in FIG. 20.

FIG. 21 is a side view, in partial cross-sectional, of anelectroporation catheter assembly similar to the examples of FIGS. 11and 18.

FIG. 22 is a side view of a stent-like temporary scaffold or structureaccording to many embodiments.

FIG. 23 is a magnified top view of the interwoven filaments of astent-like temporary scaffold or structure according to manyembodiments.

FIG. 24 is a magnified perspective view of non-scoring filamentsinterwoven and received within a notch of a scoring filament in astent-like temporary scaffold or structure according to manyembodiments.

FIG. 25 is a side view of a scoring filament having a plurality ofnotches for receiving a plurality of non-scoring filaments in astent-like temporary scaffold or structure according to manyembodiments.

FIGS. 26A to 26C are side views of a plurality of scoring members of ascoring filament in a stent-like structure according to manyembodiments.

FIG. 27A is a cross-sectional view of an occluded blood vessel prior totreatment in accordance with many embodiments.

FIG. 27B-27D are cross-sectional views of a stent-like temporaryscaffold or structure disposed over an expandable element as used totreat the blood vessel occlusion of FIG. 27A in accordance with manyembodiments.

FIG. 27E is a cross-sectional view of the occluded blood vessel of FIG.27A after the treatment of FIGS. 27B-27D in accordance with manyembodiments.

DETAILED DESCRIPTION OF THE INVENTION

The following description will typically be with reference to specificstructural embodiments and methods. It is to be understood that there isno intention to limit the invention to the specifically disclosedembodiments and methods but that the invention may be practiced usingother features, elements, methods and embodiments. Preferred embodimentsare described to illustrate the present invention, not to limit itsscope, which is defined by the claims. Those of ordinary skill in theart will recognize a variety of equivalent variations on the descriptionthat follows. Like elements in various embodiments are commonly referredto with like reference numerals.

FIG. 1 shows a typical synthetic graft 10 used in hemodialysis. Thegraft extends between a vein 12 and an artery 14. The graft 10 may beabout thirty centimeters long with an inner diameter (ID.) of 6 or 7millimeters. A catheter 16 can be inserted through the wall of the graftor vessel. Typically, the catheter might have an outside diameter (O.D.)of 2.7 mm and an inner diameter (LD.) of 2.3 mm. A malecot typeexpansion device 18 may be covered with a membrane 20 (see FIG. 4). Whenexpanded, it can serve to block the annular space between the outsidewall of the catheter 16 and the graft 10. A support wire 22 for abraided removal mechanism 24 will typically have an outside diameter ofabout one mm and has an internal actuator rod 26 (see FIG. 2) ofapproximately 0.5 mm. Because of the simplicity of the design, thisoutside diameter could be smaller than 0.5 mm. In FIG. 1, the malecottype blocking device 18 and the braided removal device 24 are both shownin their expanded state and are positioned so that retrograde orproximal movement of the support wire 22 will pull the braided elementin a proximal direction to push out whatever coagulated blood is betweenthe braided device 18 and the distal end of the catheter into thecatheter opening where it can be aspirated; thereby clearing theblockage in the graft or other vessel.

The structure of FIG. 1, which has been tested, was designed for use ina hemodialysis graft 10 having an I.D. of approximately six to seven mm.In the tested case, the catheter 16 has an 8 French O.D. (2.7 mm) and a7 French I.D. (2.3 mm). The support wire 22 comprises a fairly standardmovable core guide wire of 35 mils (that is, 0.35 inches, which isslightly under 1 mm). The actuator rod 26 in the support wire may beapproximately 15 mils and thus slightly under 0.5 mm. The braidedelement 24 may have an insertion diameter that is approximately one mmand may expand to cover the seven mm diameter of the graft. In order toachieve this seven fold increase in diameter, the braided element canhave a length of 11 to 13 mm. Thus, the catheter can have an annulus ofabout 2.3 mm around the support wire, through which annulus the bloodocclusion is aspirated.

FIGS. 2 and 3 illustrate the support wire 22 and braided element 24which constitute the occlusion engaging element that is moved proximalto push the occlusion into the catheter for removal. A preferredocclusion engaging element 24 may comprise a braided element. Thebraided material often has a stiffness such that it will not collapse orfold under the pressure of the occlusion when this engaging element isbeing moved proximally. Yet, the filaments that form the braid oftenmust be flexible enough to be moved between the two states as shown inFIGS. 2 and 3. Materials from polyester to stainless steel can besuccessfully used.

The distal tip of the braided element 24 may be connected to the distaltip of the actuator rod 26. The proximal edge of the braided element 24may be bonded to the distal end of the support wire 22. Thus, when theactuator rod 26 is pushed in a distal direction relative to the wire 22,the braided device can be forced into its collapsed state shown in FIG.2 and is available to be pushed through the catheter and through oraround the occlusion which is to be removed. When this engaging element24 has been fully inserted, the actuator rod 26 may be moved in aproximal direction causing the braided element 24 to take the expandedposition such as that shown in FIG. 3 so that subsequent movement of theentire support wire 22 can cause the braided element to move against theocclusion and push the occlusion into the distal end of the catheter. Insome circumstances, the braided element 24 might be left as a braid withopenings because the portions of the occlusion which may pass throughthe openings will be sufficiently smaller liquids so that they do nothave to be removed. In other circumstances, it may be desirable to coverthe braided element 24 with a membrane or film so that it becomessubstantially impermeable. Further the membrane or film covering theengaging element will be helpful in preventing trauma to the inner wallsof native tissue. Even further, this membrane may be helpful inoptimizing the physical characteristics of the engaging element.

With reference to FIG. 1, it might be noted that when the braidedelement is pushed all the way down to one end of the graft 10, as shownin FIG. 1, and then expanded, the braided element will typically beexpanding against a portion of the wall of the graft that is smallerthan the bulk of the graft. However, as the support wire 22 is pulled tomove the braided occlusion removal element proximally, the braidedocclusion element can ride on the wall of the graft and can expand asthe wall of the graft expands as long as tension is maintained on theactuator rod 26.

There might be applications in accordance with many embodiments of thepresent invention where the passageway involved is a tissue passagewaysuch as a blood vessel or other channel within the body, where thisbraided element 24 is expanded to nearly the diameter of the vessel sothat when it is moved to push out an occlusion, it will avoid trauma tothe wall of the vessel. Further, the membrane on the expanding elementwill aid in decreasing the trauma to native vessels as described above.In such a case, the engaging element (and the blocking element) may beused only as a seal so that the obstruction may be removed or otherwiseobliterated. This seal can allow the rest of the vessel to beuncontaminated and can provide for a closed system for irrigation and/oraspiration and subsequent obliteration or removal of the obstruction.

FIG. 4 illustrates the catheter 16 with the malecot 18 in an expandedstate on the distal end of the catheter. A membrane 20 is normally usedin order to provide a complete blocking or sealing function. Further,the membrane 20 may aid in locking the blocking element in a particularshape. This malecot type element can be created by making longitudinalslits in the sidewall of the catheter (or an attachment bonded thereto)thereby creating links or wings that will expand when the distal end ofthe catheter is pushed in a proximal direction. The appropriate pushingof the proximal end of the catheter can be achieved, as shown in FIG. 5,by a ferrule 30 which is a standard tip on a standard dilator 28.Alternatively or in combination, the dilator 28 may be a guide wire(which is usually much longer and flexible than a dilator) for remoteobstruction removal. In such an application, the guide wire may have aferrule type mechanism that may act like the ferrule on the dilator. Inthis instance, the guide wire (with ferrule) may be inserted into thevessel to the obstruction. The catheter may then be pushed along theguide wire until it reached the ferrule which would normally be locatednear the distal end of the guide wire. At this point, the wire may bepulled back, the ferrule may butt against the catheter and force out theblocking sealing element. The engaging element may be used with thisblocking element and it could even be the ferruled wire as well.

It should be noted that the retention catheter described in U.S. Pat.No. 3,799,172 issued on Mar. 26, 1974 to Roman Szpur illustrates astructure that is similar to the malecot type device 18 illustrated inFIG. 4; although in that patent it is used as a retention device whereashere it is used as a blocking element.

This blocking element 18 is often called a malecot in the industry. Itshould be understood herein that the term malecot is generally used torefer in general to this type of multi-wing device.

More specifically, as shown in FIG. 5, the catheter 16 together with adilator 28 having an expanded tip 30, which is a ferrule, can beinserted into a vessel 32 such as the graft shown in FIG. 1. Thecatheter 16 and dilator 28 may be inserted close to the occlusion 34 andthen the dilator 28 may be removed. Proximal motion of the dilator 28may cause the tip 30 to contact the distal end of the catheter 16forcing the distal end of the catheter to put pressure on the malecotwings creating the expansion shown in FIG. 6 (and also schematicallyshown in FIG. 1). Once this expansion has occurred, the dilator with itstip can be removed from the catheter (as shown in FIG. 6).

What then occurs is shown in FIGS. 7 and 8. As shown in FIG. 7, thesupport wire 22 with its braided removal element 24 may be inserted inthe collapsed state so that it passes through or around the occlusion34. It should be noted that the support wire 24 may be inserted prior tothe blocking catheter being inserted or after the catheter is inserted(the latter of which is illustrated in the FIGS.). Most of theocclusions to which the device of FIGS. 1-8 is directed, such ascongealed blood in a graft, will permit a support wire 22 to passthrough it because the consistency is that of viscous material which canbe readily penetrated. Alternatively, if the occlusion is a non viscousmaterial such as a stone, plaque, emboli, foreign body, etc. the supportwire 22 is small enough to be passed around the occlusion. Once thebraided element 24 is on the distal side of the occlusion 34, theactuator rod 26 may be pulled, creating the expanded state for thebraided device. Accordingly, distal movement of the entire support wiremay cause the expanded braided device to move against the occlusion andforce it into the catheter for removal with or without aspiration. Whenremoval of obstructions that are located some distance away from thepoint of access into the body such as the carotid artery via a groinaccess the wire 22 would likely be inserted first. In this case, thesupport are 22 with its expanding element 24 may be used as a guide wireto guide the catheter to the preferred location. Of further import isthat the blocking element and the engaging element may be used withoutany relative motion once deployed. Such is the case when irrigationand/or aspiration is used for the obstruction removal. In this case, thetwo elements can be used as seals against the tubular inner walls onboth sides of the obstruction whereby the obstruction is removed fromthat sealed space with the use of aspiration, irrigation, or both.Further other means of obliterating the obstruction within this sealedspace may be employed. Some of those means are, but are not limited tothe addition of dissolving agents, delivery of energy such asultrasound, laser or light energy, hydraulic energy and the like.

Other Comments

An important consideration of the device described herein is that thesupport wire with its expanding element can be fabricated with a verysmall diameter. This may be important because it allows an optimallylarge annular space between the wire and the inside of the catheter formaximum obstruction removal. Previous engaging elements have been usedthat use a balloon for the engaging element. This balloon design mayrequire a larger shaft diameter than that of the presently describednon-balloon designs according to many embodiments. Hence in theseprevious devices, the annular space is not maximized as in the presentlydescribed non-balloon embodiments. The term wire may be used to refer tothe support portion of the removal device. The material of the wire neednot necessarily be metal. Further, it may be desirable to use a ‘double’engaging element (i.e. two braided or malecot expanding elementsseparated a distance appropriate to entrap the occlusion) in the casefor example where the occlusion is desired to be trapped in the vessel.The term wire may be used herein to refer to a dual element devicehaving a shell component and a core or mandril component which arelongitudinally moveable relative to one another so as to be able toplace the braided occlusion engaging element into its small diameterinsertion state and its large diameter occlusion removal state.

Although the blocking element is often described as a malecot type ofdevice, it should be understood that the blocking element may bedesigned in various fashions which are known in the art. See, forexample, FIGS. 9 and 10. As another example, an appropriately designedbraid arrangement could be used as the blocking element. In that case,the catheter may have to be a dual wall catheter in which the inner andouter annular walls are able to move relative to one another in alongitudinal direction so as to place the braid used as a blockingelement in its small diameter insertion state and its large diameterblocking state. Alternatively, it may be a single wall similar in designto the malecot style blocking element described previously.

It should be further understood that there might be a situation in whichthe blocking element or even the occlusion engaging element would beprovided to the physician in a normal expanded state so that when thedevice is deployed, it would, through plastic memory or elastic memory,automatically snap into its expanded state.

Discussion of Method for Treating a Target Site in a Vascular BodyChannel

The above-described structure and methods provide a good background forthe following description of the presently claimed invention.Corresponding structures are referred to with corresponding referencenumeral, such as support wire 22/support wire 122, and occlusion34/occlusion 134.

FIG. 11 illustrates a catheter assembly 100 including a proximal endportion 101, from which proximal occluder catheter shaft 116 extends andpasses into blood vessel 132, and a distal end portion 96 at a targetsite 98 within blood vessel 132. Distal occluder 124 is typicallypositioned at a location distal of target site 98 while balloon typeproximal occluder 121 is typically positioned at a location proximal ofthe target site to define a region 109 therebetween. Occluders of typesother than those illustrated as proximal and distal occluders 121, 124,such as malecot type occluders, can also be used. However, the annularballoon type of proximal occluder 121 illustrated may be preferred forits simplicity of construction and lower cost. Catheter assembly 100also includes a balloon assembly 105 comprising a balloon catheter shaft104 passing through proximal occluder catheter shaft 116 with a balloon102 at its distal end. Support wire 122, with an actuator 126 passingtherethrough, extends from distal occluder 124 and passes throughballoon catheter shaft 104. Balloon 102 is shown in an expanded statepressing against occlusion 134. If desired, balloon 102 may comprise adrug eluting balloon. FIG. 11 also shows an injected agent 111 withinregion 109. Agent 111 may include various types of therapeutic and/ordiagnostic agents, such as paclitaxel, sirolimus, otheranti-proliferative drugs, contrast agent, thrombolytic agent, stemcells, agents to dissolve the obstruction, agents to change a vulnerableplaque to a non vulnerable plaque and the like. As discussed in moredetail below, agent 111 acts on the occlusion 134 and the inside surfaceof a vessel 132 at the target site 98 during the intervention, in thisexample by balloon 102.

FIGS. 12-14 show the initial steps during the use of catheter assembly100. These steps correspond to FIGS. 5-7, discussed above, with anexception that occlusion 134 does not totally block blood vessel 132.FIG. 15 is similar to FIG. 8 but also shows the introduction of injectedagent 111 into region 109 between proximal occluder 121 and support wire122. In some embodiments, the region 109 is aspirated through cathetershaft 116 prior to injecting agent 111. The use of proximal and distaloccluders 121, 124 may concentrate agent 111 at and around occlusion 134at target site 98. FIG. 16 also shows balloon catheter shaft 104, with aballoon 102 at its distal end, inserted over support wire 122 untilballoon 102, in its deflated state, is positioned at occlusion 134. FIG.17 shows balloon 102 expanded against occlusion 134. Balloon 102 canthen be deflated, back to the state of FIG. 16, followed by the removalof balloon assembly 105 to the condition of FIG. 15. Region 109 can thenbe aspirated to remove material from the region; the aspiration may bein conjunction with pulling distal occluder 124 proximally at least partof the way towards proximal occluder 121 and/or partial collapse ofdistal occluder 124 to permit retrograde blood flow past the distalocclude 124 and into region 109. Alternatively, the contents of region109 may be allowed to flow downstream as the total dose administeredwould likely not be harmful to the patient. After aspiration of region109 is complete, distal occluder 124 can be collapsed to the conditionof FIG. 14 and pulled back into catheter shaft 116. Proximal occluder121 is collapsed by deflating balloon 102 through balloon catheter shaft104.

The entire time balloon 102 is operating on occlusion 134, or some otherintervention is being conducted at the target site 98, agent 111 may bepresent to bathe target site 98, including occlusion 134 and the innerwall of blood vessel 132 between occluders 121 and 124. This aspect ofthe invention may be highly important because both the intervention,such as with angioplasty balloon 102, and the injected agent therapy areconducted essentially simultaneously without the need for removal andreplacement of catheters and interventional tools.

In some embodiments, proximal and distal occluders 121, and 124 aremaintained in place to maintain agent 111 at target site 98 for a periodof time, such as several minutes to hours, after balloon 102 has beencollapsed. In some situations, more than one target site 98 may betreated through the placement of occluders 121, 124 in contractedstates, moving the occluders to a new target site, re-expanding theoccluders to their expanded states followed by injecting a agent 111into the newly created region 109 and performing an intervention at thetarget site, typically using a balloon 102.

Ever since stents were introduced in the 1980's, investigators havesearched for devices and methods to provide temporary support to thevascular wall without leaving a stent, which can never be removed, inthe vessel forever. Bare metal stents have an unacceptable restenosisrates, and drug eluting stents, while having a moderately acceptablerestenosis rate, are extremely expensive, have long term sequelae suchas late stent thrombosis, and patients must stay on costly andpotentially dangerous platelet inhibitor and other drugs for one year tolife. Biodegradable and bioabsorbable stents have been proposed andproduced, but they are less effective than either bare metal stents ordrug eluting stents.

One particular use of devices according to many embodiments is toutilize part or all of the system before a bare metal stent (BMS)delivery. Drug eluting stents (DES) deliver the drug to only a smallportion of the vessel wall that is stented because of the spaces betweenthe drug eluting stent struts. Utilizing the current device with theagent injected into the closed space 109 before expansion of a BMS wouldbathe 100% of the vessel wall and still have the stent present tocounteract elastic recoil, if it did occur, remodeling of the vessel,dissections, and other problems associated with vascular interventions.The BMS could be used with the proximal and distal occluders primarily.Alternatively, the temporary balloon stent apparatus could be utilizedwith the occluders and the agent between them as outlined below. Ifthere was an unsatisfactory result after treatment with the entiresystem of occluders, agent, and temporary balloon stent, then the BMSmay be deployed as a “bail-out” procedure. The agent may or may not bereapplied, having already been utilized before the aforementionedtemporary stent application.

The prior art does not address a removable balloon stent apparatus thatdilates the plaque and supports the wall after plaque dilatation.Lashinski et al. in U.S. Pat. No. 6,773,519 describe a stent like devicewhich is deployed and then removed, and describes a removable couplerwhich is part of the device, but not a removable stent. Tsugita in U.S.Pat. No. 6,652,505 describes a guided filter which may be used todeliver a stent and removed, but not a removable stent. Kahmann in U.S.Pat. No. 5,879,380 describes a device and method for relining a sectionof blood vessel that has been injured or removed, not a device to bothdilate the lesion and prevent elastic recoil as does the manyembodiments of the present invention discussed below with reference toFIGS. 18-20.

Further embodiments of the present invention will be described withreference to FIGS. 18-20. This example is intended to dilate theocclusion 130 and inhibit elastic recoil by providing temporarystenting. Balloon assembly 140 includes balloon catheter shaft 104 withballoon 102 at its distal end and an actuator sleeve 144 surroundingballoon catheter shaft 104. A radially expandable braid 142 can bepositioned over balloon 102. Balloon 102 and braid 142 are shownexpanded in FIG. 18. The distal end 146 of braid 142 may be secured tothe distal end of balloon catheter shaft 104 while the proximal end 148of braid 142 may be secured to the distal end of actuator sleeve 144.Therefore, braid 142, although a stent like structure, comprises anonremovable part of balloon assembly 140 and can be removed from thepatient following the procedure.

FIG. 19 shows balloon 102 and a collapsed state and that by moving theactuator sleeve 144 distally in the direction of arrows 150, the braid142 may become expanded over the collapsed balloon 1, as shown in FIG.19, and will stay expanded when balloon 102 is deflated and collapsed.The braid 142 is fixed to the catheter shaft 104 distally, but not tothe balloon 102. It is in this expanded state of braid 142 and collapsedstate of balloon 102 that the braid can act as a stent like structureand allow blood flow to be restored.

In FIG. 20, by moving the actuator sleeve and 44 proximally in thedirection of arrows 152, the braid 142 will be contracted against thedeflated and collapsed balloon 102, and may even help lower the profileof the collapsed balloon. It is in this contracted state that balloonassembly 140 is typically inserted and removed.

Balloon assembly 140 can be used by itself, that is, not as areplacement for balloon assembly 105 of catheter assembly 100 of FIG.11. However, by using balloon assembly 140 as a part of catheterassembly 100 additional advantages can be achieved. Four separate butcomplementary actions can be achieved relative to the inside surface ofblood vessel 132 and occlusion 134: 1) It provides a time proven balloonaction to effectively dilate the occlusion, 2) It provides a mesh braidover the balloon to more evenly apply stresses on the plaque and thuscause less dissection and injury, 3) The braid, acting independently ofthe balloon, acts as a transient, removable stent to lessen acuteelastic recoil, and 4) When combined with a drug delivery, it willinhibit restenosis. Currently, there are several companies in variousstages of development and commercialization of drug eluting balloons.However, these devices do not possess the mechanical advantages providedby many embodiments of the present invention, i.e., the braid to createcrevices that allow the plaque to be more homogeneously compressed atlower pressures with less injury, and the ability of the braid to beused as a transient, temporary, or removable stent to reduce theincidence of acute elastic recoil and flow limiting dissections, andacting in concert with the agent to prevent restenosis. Drug eluting anddrug coated balloons do indeed provide an advancement over plain oldballoon angioplasty (POBA) by lessening the incidence of restenosis from40-60% to 10-15%. However, restenosis is only one of three majorproblems associated with POBA. The other two, acute elastic recoil andflow limiting dissections, are not addressed by drug eluting and drugcoated balloons. Hence, there will still be a need to place a stent toaddress these two major problems when they occur, and they occur in upto 40-50% of cases in some studies. In most of these cases, “bail out”or unintended stenting will be needed to address the acute recoil andthe flow limiting dissections that occur. The recoil and dissectionphenomena are so common that many practitioners actually proceeddirectly to stenting to save time and complete the intervention withgood results rather than attempt to perform just an angioplasty prior todetermining the need for stenting. This can add cost to the procedureand leave a metal structure in the patient which may cause otherproblems such as late stent thrombosis, in-stent restenosis, stentfracture, stent malapposition, and others. These sequalae of the stentplacement can often be very difficult to address when they occur. Hencethe drug eluting and drug coated balloons are only a partial solution tothe dilemma. Utilizing them with the embodiments according to thecurrent invention, however, can provide a complete solution to the threemajor deficiencies of POBA.

Aspects of the present invention can address all three primarydeficiencies of POBA without the need for stenting or foreign materialsto be permanently placed within the vessel to maintain a channel forblood flow. Restenosis is addressed, as are drug eluting and drug coatedballoons, by providing delivery of a drug or other substance to inhibitrestenosis, whether by fluid administration between proximal and distaloccluders or via a drug eluting balloon or a drug coated balloon. Manyembodiments in accordance with the present invention support the wall ofthe vessel after dilatation to prevent or severely lessen the occurrenceof flow limiting dissections. Many embodiments in accordance with thepresent invention also support the wall while the drug is acting on thesmooth muscle cells to cause them to relax and hence prevents acuteelastic recoil. By performing these three actions, the need for stentingwill be significantly lessened if not eliminated in most cases. This isnot the case when utilizing drug eluting or drug coated balloons withoutthe current invention.

When the temporary scaffold described herein is utilized with a drugcoated or drug eluting balloon, the proximal and distal occluders maynot be used in at least some cases. The proximal and distal occludersfunction to contain the liquid drug or substance within a closed spaceor focal area of the blood vessel. Since the drug or substance is eitheron the surface of the balloon (drug coated balloon) or within theballoon (drug eluting balloon), there may be no need for the proximaland distal occluders to contain the drug or substance in at least somecases. In this instance, the drug coated or drug eluting balloon may beplaced within the braided or stent like structure that comprises thetemporary scaffold and used to dilate the lesion similar to the balloondescribe elsewhere. Alternatively, the lesion may be dilated by astandard POBA balloon beforehand and then the temporary scaffold devicecomprising the drug eluting or drug coated balloon may be appliedsubsequently. This may necessitate a catheter exchange, and may notprovide some of the advantages of fluid drug or other substanceadministration in at least some cases, but certainly may be effective.

Because the braid 142 is not attached to the balloon surface, it can actindependently of the balloon 102. It is normally expanded with theballoon, but when the balloon is contracted or collapsed to allow fordistal blood flow to recommence, the braid can be locked into anexpanded configuration by manipulating catheter shaft 104 and actuatorsleeve 144 with one's fingers. It is proposed that by leaving the braidexpanded for several minutes while blood flow is restored distally, thesmooth muscle will accommodate the stretch of the angioplasty. This maywell diminish the incidence of acute elastic recoil, one of the majoracute problems of POBA. In fact, prolonged expansion of the vessel hasjust this effect; however, the time that a balloon can be left expandedis limited as ischemia will develop.

The sum of these advantages, i.e., the mechanical advantages of thebraid in dilating the plaque with less pressure, less dissection, andless injury along with the temporary stent usage further combined withdrug elution to inhibit restensosis can significantly improve patientoutcomes.

Many embodiments in accordance with the present invention have thepotential to dramatically improve the results of POBA and the potentialto improve the results of and replace DES in many cases, especially dueto the ability to block the effects of recoil. Such cases includepatients with in-stent restenosis, bifurcation lesions, and smallvessels lesions. DES will likely remain a dominant strategy in treatingmany lesions and there will likely always be a need for stenting,atherectomy and other complex treatments; but clearly if feasibility isshown, many embodiments in accordance with the present invention couldbecome the treatment of choice for most angioplasty procedures. In thosecases in which it may not achieve optimal results, BMS (or even DES) maythen be utilized.

Embodiments according to the present invention may occlude the lumenwith a device that will allow the angioplasty catheter shaft 104 to passthrough it, and by occluding the distal aspect of the vascular channelto be perfused with the agent, the angioplasty balloon 102 and/or stentdelivery balloon assembly 140 may be placed through the proximaloccluder catheter shaft 116 and over the support wire 122 of the distaloccluder device, the drug infused and the angioplasty and/or stentdelivery can take place while the drug is present. This may allow thepressure of the angioplasty balloon 102 and/or stent delivery balloonassembly 140 to force the drug into the vessel wall while theplaque/vessel is being dilated. The drug can be delivered during theprocedure and before platelet adhesion would prevent some of the drugfrom accessing the vessel wall as in the case of existing prior art. Thepresence of the drug while the action on the plaque or vessel is takingplace can deliver more drug to the vessel wall than just passivelybathing the vessel after the intervention.

The procedure could take several forms but an exemplary method would beto perform an angiogram to identify the lesion to be treated at thetarget site 98. After the lesion is identified, a diagnostic cathetermay be advanced beyond the occlusion 134 and the distal occluder 124,which is support wire 122 and pull wire 123 based, may be deployed.Distal occluder 124 may essentially comprise a mesh braid covered withan impermeable substance. The diagnostic catheter can be removed and theproximal occluder catheter shaft 116, with proximal occluder 121 at itsdistal end, can be inserted over the guide wire/distal occluder and thetip of the proximal occluder may be positioned proximal to the lesion.The proximal occluder could be balloon based or non balloon based. Thereis a mesh braid funnel catheter occluder invented by the currentinventor which occluders without the use of a balloon; see U.S. Pat. No.6,221,006, the disclosure of which is incorporated by reference. Theproximal occluder 121 and then the distal occluder 124 may be activatedso that compete occlusion of the vascular lumen would be achieved. Theblood would be aspirated from the region 109 between the proximal anddistal occluders. The agent would be injected as injected agent 111. Theagent and its concentration would be determined by the physician. Theagent usually would be mixed with contrast so that it would be visibleunder fluoroscopy. The angioplasty balloon assembly 105 or the stentdelivery balloon assembly 140 device or a stent delivery device (notshown) with a BMS or DES would be placed over the support wire 122 ofthe distal occluder 124 and centered on occlusion 134. The angioplastyor stent delivery can then be performed within this closed system withthe agent in place. The angioplasty balloon assembly 105 or stentdelivery balloon assembly 140 could then be removed through the proximaloccluder 121, and the agent aspirated. The distal occluder 124 would bereleased and further aspiration done until blood was returned insuringthat all of the drug had been aspirated before releasing the proximaloccluder. The proximal occluder 121 would then be released, restoringblood flow distally.

Alternatively at this point of the procedure, if a second dilatation wasdesired, the drug could be aspirated through the proximal occluder afterthe initial dilatation similar to the above procedure, but before theangioplasty balloon was removed. Similar to above, the distal occludermay be released first while still aspirating. After blood was returnedin the aspiration fluid, assuring that the entire amount of drug hadbeen aspirated, the proximal occluder may be released restoring bloodflow distally. A second dilatation of the angioplasty balloon could thenbe performed in a standard conventional manner without any drug beingpresent, the drug having been delivered during the first dilatation.

However, if the desire was to deliver drug during the second dilatation,then the procedure above for the first dilatation may be repeated in aslightly modified manner. There would usually be no need to remove theangioplasty balloon. The proximal occluder would be activated, followedby the distal occluder. The blood aspirated and the drug injectedthrough the lumen of the proximal occluder, and around the shaft of theangioplasty balloon. Then, the second angioplasty dilatation could takeplace, the drug aspirated, the distal occluder released duringaspiration, and the proximal occluder released to restore blood flow.

If two separate lesions in the same vascular region needed to betreated, the above may be modified somewhat. After the first lesion wastreated as above, the occluders, balloon and temporary balloon stent maybe collapsed and moved to a second location where the procedure would berepeated without the laborious step of changing catheters and so on.This would save time and cost, as most balloon catheters cannot bewithdrawn and then reinserted into the body as the balloon folds causereinsertion to be difficult and impractical.

If balloon assembly 140 were utilized in the above procedure instead ofa conventional angioplasty balloon, braid 142, acting as a temporarystent, may remain expanded against the vessel wall in a stent likemanner during the first balloon inflation, between inflations, duringthe second balloon inflations and for a chosen period after the lastballoon inflation. This action would not only effectively deliver thedrug to the vessel wall, but also would provide a temporary stentingeffect to the vessel wall to inhibit acute elastic recoil.

Moreover, if balloon assembly 140 were utilized it would provide lessinjury to the vessel wall by dilating the occlusion at lesser pressuresand causing fewer dissections. Therefore, the essence of this procedureis to create less damage to the vessel wall, prevent elastic recoil,compress the plaque efficiently, and to deliver a drug to inhibitintimal hyperplasia as a cause of restenosis.

This procedure has many different ways of being performed as a standardangioplasty balloon, such as balloon 102, may be used, a specialtydevice, such as a balloon assembly 140, may be used; in addition, stentdelivery devices, laser devices, cryoplasty and most any device designedfor endovascular treatment of vascular disease may be used in accordancewith the present invention. Devices according to many embodiments of thepresent invention differ from prior art in that a non-balloon distaloccluder is preferably used in the procedure. This one step can make itpossible to perform the drug perfusion and the intervention in a singlestep vs. the cumbersome method of having to exchange catheters and thendeliver the drug after the fact, or at least after the intervention.While other components of this device are present for the purpose ofperfusing drug after angioplasty, the presence of a guide wire (supportwire 122) occluder, with any type of proximal occluder that could betraversed by a catheter, can make devices according to many embodimentssuperior ones as they allow the intervention to be performed while thelesion and vessel wall are being bathed by the drug or other agent. Ofcourse, a balloon occluder may be used distally in the method describedabove if it contained a shaft thin enough for an inflation channel andmeans to allow insertion of a treatment device coaxially over the distaloccluder shaft, and it is included by this mention as an alternativeembodiment.

The one feature of the ability to place the treatment device over theshaft of the distal occluder so that the treatment is conductedconcurrently with the drug delivery can be important to the commercialsuccess of the procedure and method of infusing a drug to inhibitrestenosis as it can obviate the less than effective method ofdelivering the drug in a second step in an inefficient manner after theintervention, and with a good deal of pressure upon the vessel wall.Therefore, an aspect of the present invention relates to performing theinterventional procedure while the agent is contained within thevascular space. Aspects of the present invention may permit treatment ofvariable lengths of vessel with the one device vs. the fixed lengths ofdevices for treating vessels in prior art. If an arterial segment thatis stenosed is for example, 1.0 or 2.5 cm in length, then the entireocclusion 134 can typically be treated with a single placement ofproximal and distal occluders 121, 124. If the lesion is 25 cm or 50 cmor 100 cm in length, then the same device can be used to treat any ofthose lesions by varying the length between the proximal occluder andthe distal occluder to treat the desired length as the proximal anddistal occluders are not connected by a fixed distance as in the priorart. In long lesions, the prior art devices would need to successivelymove the fixed distance proximal and distal occluders (usually balloons)and provide short overlaps between each segment for multiple segmentsand multiple treatment sessions. The methods according to manyembodiments of the present invention would therefore save time, obviaterepeated repositioning of the prior art device and obviate the use ofmultiple doses of the drug or other substance.

Balloon assembly 140 is inserted into blood vessel 132, positioned atocclusion 134, and the balloon 102 inflated in a standard manner. Theinflation of the balloon may expand the braid 142 and this is the usualmethod of expansion of the braid. More importantly is that the lesioncan be dilated successfully, probably with a lesser pressure than aconventional POBA balloon. See FIG. 18. After a first length of timechosen by the operator, typically one or two minutes, the balloon can bedeflated while force is exerted on the actuator sleeve in the directionof arrows 150. See FIG. 19. This can keep the braid 142 expanded againstthe vessel wall while the balloon 102 is contracted allowing for bloodflow to be restored distally for a second length of time, usually morethan 3 minutes and typically 3 to 90 minutes. The proximal occluder andof the distal occluder can be collapsed after the balloon is deflated torestore flow in the vessel while the braid is expanded against thevessel wall. The balloon inflation may be repeated as many times asdesired, and by keeping forward force on the actuator sleeve 144, thebraid 142 can remain expanded during, between, and after ballooninflations. There may be a locking mechanism provided so that theforward force can be maintained without manual pressure. Moreover, thetemporary stent may be used with modalities other than drugs, such asradiofrequency, electroporation, heat, atherectomy, gene therapy,cryotherapy, electrical currents, radiation, iontophoresis, otherpharmacological agents and substances, and the like.

Another alternative configuration of the temporary stent 140 as shown inFIGS. 18, 19, and 20 would be to coat the balloon 102 with an excipient(not shown) that contained a drug such as, but not limited to,paclitaxel, and to use a stent like structure over this specialtyballoon as demonstrated in these figures. The stent like structure mayor may not be braid, and may be a self expanding stent even. Thedelivery of the drug directly from the balloon may obviate the need forthe proximal and distal occluders previously described as the drug wouldbe delivered from the coated balloon 102 rather than as a fluid withinthe closed space. Another alternative may be to utilize a porous drugeluting balloon (not shown) instead of the balloon 102 shown in thesefigures. In this instance, the drug or substance to be delivered may beinjected into the porous balloon and delivered from the porous balloonto the vessel wall by a weeping method or the like.

As well a temporary stent could be fitted over the drug coated balloonor drug containing porous balloon as a separate device rather than beingfixably attached to the balloon as has been discussed previously.

A temporary stent 140 placed coaxially over the balloon 102 which is notattached to an actuator sleeve 144 as in FIGS. 18-20 can also be analternative configuration. This stent like structure may be a selfexpanding non braided stent which would overcome some deficiencies ofmesh braid such as poor radial strength, pronounced foreshortening,overlapping thicknesses and the like. It may be braid however. The stentmay or may not be attached to the actuator sleeve 144 and the distalcatheter 146. If not attached to these, it may be attached to a distalwire described below and at least one wire proximally, or to acombination of wires and actuator sheaths. If utilized with the funnelshaped proximal occluder previously mentioned, the stent structure maybe collapsed and retrieved by the combination of forward force on thedistal wire, traction force on the proximal wire(s), and by pulling theapparatus into the mouth of the funnel occluder catheter to retrieve it.The use of wires would save precious space by obviating the need for anactuator sleeve which typically would utilize at least 1 Fr. (0.013″) inspace because of wall thickness.

If a self expanding stent is utilized, it may be mounted over theballoon coaxially and constrained in a compressed configuration insideof a specific delivery device, or even preloaded into the lumen of theproximal occluder catheter. In the latter case, the proximal occludercatheter may initially be positioned at the lesion to be treated eitherprimarily or after pre-dilation of the lesion with another angioplastyballoon. Withdrawal of the outer proximal occlusion catheter withforward pressure on the temporary stent apparatus may deliver thetemporary stent and balloon apparatus to the site to be treated. Theinflation of the balloon may dilate the lesion, the self expandingtemporary stent or scaffold may hold the vessel open. Subsequently, theballoon and the temporary stent may be withdrawn into the proximalocclusion catheter or the specific delivery catheter mentioned above.

In even another alternative embodiment, the temporary stent alone may beutilized in a configuration that does not involve a coaxial positionover the balloon. The balloon may be used completely separately and notattached to the temporary stent. In other words, the temporary stent maybe used subsequently to the balloon dilatation as a planned procedure ora “bail out” procedure because of a flow limiting dissection, recoil, orother reason. In this configuration, the temporary stent may beconfigured as in FIGS. 18-20 but without the balloon 102. It may beattached to wires as previously discussed or some other means tocontract and expand it. However, experiments conducted have shown thatit is advantageous to expand a balloon within the closed spacecontaining the drug as the expansion of the balloon creates addedpressure within the closed space and essentially drives the drug orother substance into the vessel wall. There is significantly more drugwithin the vessel wall when done under pressure than when just passivelyinfused into a closed space. The drug also penetrates deeper into thevessel wall with the added pressure than without it and reaches themedia and adventitia. In the case of restenosis, the inhibition ofsmooth muscle cell proliferation and migration in and from the media isof extreme importance. The expansion of the balloon while the drug ispresent within the closed space will make drug delivery to all levels ofthe vessel wall more efficient and effective.

To insure that adequate pressure is achieved within the closed space, asensor may be placed on the temporary scaffold or either the proximal ordistal occluders of the system. Another simple method may be to performexperiments measuring pressures within isolated segments of animalsvarying the diameter and length of the segment to be isolated and thediameter and length of the expanded balloon, and developing a table ofthe variables which indicates the volume of fluid needed to achieve thedesired pressure within the isolated segment corresponding to apreviously determined value. This may obviate the need for an expensivesensor in every device. One of the goals of the current invention is toprovide a device which performs several complimentary actions at onetime rather than the laborious and time consuming method currentlyemployed of sequentially changing different catheters to perform theseparate and different actions desired.

As mentioned above, the scoring of the plaque will typically cause theplaque to compress more evenly and at lower pressures than with POBA.This may be a result of focal areas of force being applied to the plaquewith scoring vs. the generally uniform force of a standard angioplastyballoon. Combining the advantageous scoring features with supportfeatures of the scaffold can be problematic as scoring demands fewerfilaments or members to cut into the plaque and the scaffold demandsmore filaments or members to add strength to the device. In other words,the number of filaments needed to support the lesion after dilatationcan be significantly more than the optimum number of filaments needed toscore the lesion. Scoring of the lesion depends on providing a focalforce at one or several areas upon and within the plaque. If all of thefilaments were scoring filaments, this force may be diluted or dividedover all of the filaments and none would be dominant in directing forceinto the plaque. The force may be generalized rather than being focal,and there would be no area or areas of dominant force to cause theplaque to fracture beneath the scoring elements. Hence only a fewscoring filaments are needed to produce the desired results. Morefilaments would not produce the desired results of a few areas of focalfracturing of the plaque.

If there were only a few filaments for support, the temporaryscaffolding would not support the dilated lesion as the strength of thedevice would be diminished. Hence, there may be a trade-off between theability to score and the ability to support. This can be solved by anexemplary construction of the temporary scaffold which involves cuttingor scoring means and other separate means for supporting the vessel. Inother words, there may be specialized members of the temporary scaffoldfor cutting or scoring and other specialized members for maintaining andsupporting the vessel. Other members may be present to preventdissections even. For example, in the case of braid, the cutting orscoring means may comprise a rectangular or triangular shaped wire, orany shape which has more of a point than a standard round wire for thescoring element. A smaller or larger wire of a different shape than theremainder of the braided structure, or a smaller or larger wire orfilament that is of the same shape may be utilized as the cutting orscoring element. These wires or filaments may be directed only in onedirection of the braid, and may be interspersed amongst the other braidmembers. As well, having the larger wires directed in only one directionwould conserve valuable space as an overlapping braid creates asituation in which the diameter of the thickest wire is doubled on eachside if they were directed in a crossing fashion.

In fact, an exemplary method of obviating the overlapping dilemma isshown in FIG. 22. In this configuration, there are triangular braidfilaments 200 directed in one direction spiraling around the tubularbraid interposed amongst other braid filaments 202 directed in the samedirection and and crossing in a braided fashion the remainder of thebraid filaments 201 in a different direction. The other braid filaments201, 202 may be round, flat, rectangular or any shape, but preferablythey are lower profile than the triangular braid filaments. In someembodiments, the triangular braid filaments have notches 203 placed toreceive the other braid filaments 201 as they cross the triangularfilaments 200. Hence these configurations may serve two purposes: 1) Itmay conserve annular space by eliminating the overlap at the peak of thetriangular filament 200 and does not add further to the radial diamenterof the braid, and 2) It may preserve the scoring aspect of the apex ofthe triangle by eliminating the overlap of a braid filament that wouldinhibit the penetration of the triangular filament into the plaque.Hence a lower profile device can be maintained while enhancing thescoring properties of the device.

The number of cutting or scoring filaments may be from one to several.The fewer cutting or scoring filaments, the more force exerted on theplaque per cutting or scoring filament, hence the more effective atscoring or cutting the device will be. A preferred embodiment wouldcomprise fewer than six scoring or cutting members. Preferably, thesescoring or cutting members are oriented in a single direction.

FIG. 22 shows an exemplary braid comprising scoring wires 200 andsupporting wires 201, 202. FIG. 23 shows expanded view of a section ofthe braid device containing only the supporting wires 201, 202. Thesupporting wires or filaments 201, 202, in the case of a braidedstructure, may be standard round wires or filaments measuring preferablyfrom 0.001″ to 0.015″ in diameter. They also may be flat, rectangular,or oval, measuring from 0.0005″ to 0.010″ in thickness and from 0.003″to 0.500″ in width. To conserve space, the cutting or scoring wires ormembers 200 may measure 0.005″ to 0.009″ in greatest radial dimension orheight to the peak of the triangle, all directed in the same directionand the supportive wires or members 201, 202 measure only 0.001″ to0.005″ in greatest radial dimension or height and all directed in thesame direction. This may cause the thicker cutting or scoring wires ormembers to overlap only the thinner supportive wires or members. FIG. 24demonstrates an expanded section of FIG. 22 in which two rather flatsupporting members 201 are interwoven with a scoring member 200. Theflat supporting members 201 are present within the notches 203 mentionedabove. FIG. 25 demonstrates a section taken along the course of onescoring braid member 200. One can appreciate that the scoring member 200may cross over, and may be crossed by, the other supporting members 201.FIG. 25 shows that instead of the abrupt notches, there may be roundedindentations or other configurations (not shown) within the scoringmembers 200 to accommodate the crossing members 201. In fact, aconfiguration other than shown for illustration purposes in FIG. 25 maybe preferable in at least some instances. In fact, it may be preferableto have not notches at all in at least some instances. In thisconfiguration the crossing members would cross the apex of the scoringmembers (not shown.)

The number of members of the braid will affect the radial strength aswell as the pics per inch (the number of wire intersections per inch),the size of the central mandril, the rate of advancement of the madrilas well as other factors. Hence, any number of combinations of the typeof wire or filament, shape and dimension of the wire or filament,relative stiffness of the wire or filament, the number of the types ofwires or filaments, the total number of wires or filaments, the totalnumber of the structurally important wires or filaments, mandril size,the braid density, the pics per inch, the direction of the thick andthinner members, and other factors are possible and will contribute tothe size, strength and functionality of the scaffold. By utilizing thisnovel technique, one can optimize the cutting or scoring features, thestrength of the device, and limit the size, all important goals.

In at least some instances, a particular issue with using a braid as thescaffold is the foreshortening that often occurs when tubular braid isexpanded from its elongated configuration in which it has a reducedradial diameter for insertion and removal. When the braid is expanded,either by a balloon as in many embodiments of the present invention orby forcing the two ends of the braid closer to each other, the braidoften becomes shorter and there is often movement of the filamentslinearly. There is often movement of the filaments in a reversedirection when contracting or collapsing the braid from an expandedposition to an elongated configuration with a lesser radial diameter. Insuch movement, the braid filaments may actually cut into the plaque whenexpanding. This is not problematic as creating microfractures within theplaque is a goal of the device. However, upon contracting the braid, theelongation of the braid may cause shear forces within the plaque thatcould tear or disrupt the plaque and lead to deleterious effects such asflaps, dissections, and even extruded fragments of the plaque. Hence, inat least some instances, a majority of the filaments should preferablybe rather flat rather than rounded, square, rectangular or other shapethat may possess sharp edges that could tear or damage the tissue whenmoving in a more or less longitudinal direction. Preferably, the ratherflat members should comprise rounded edges so that these filaments wouldhave more of a compressive effect rather than a cutting effect on theplaque.

Furthermore to prevent tearing of the plaque or tissue when collapsingthe preferred braided structure according to many embodiments of thepresent invention which has mainly flat members with only a few more orless triangular scoring filaments, a mechanism may be provided so thatthe outer sleeve of the shaft of the device rotates when beingwithdrawn. It also may rotate when the balloon is expanding and thebraid is foreshortening. Hence, the braid and the scoring filaments mayrotate in a spiral manner during foreshortening (expansion) orelongation (collapsing or contracting) of the braid. The spiral motionof the scoring members upon collapsing the braid would cause them tomove within the “track” formed by the expansion and the compression ofthese filaments into the plaque. It may prevent or preclude movementinto or through tissue or plaque that had not been scored duringexpansion and would prevent or preclude damage to the plaque or tissuefrom the shear forces encountered because of the lengthening orforeshortening of the braid. The rotation or spiral motion of the outershaft may be controlled by a simple thread and groove arrangement nearthe proximal end of the outer sheath or at some other location. Othermeans may be provided to create the desired rotation or spiraling of thescoring fibers upon expansion and contraction.

In the discussion above, the scoring member 200 has been referred to atriangular. However, it may be of any shape that scores adequately. Infact, a novel shape is demonstrated in FIG. 26A, which shows a crosssection of member 200 a, the scoring member 200 a in FIG. 26A istriangular with a slightly rounded apex 205 a and more or less straightsides 207 a. FIG. 26B shows a scoring member 200 b with a more or lesspointed scoring edge 205 ba with a more or less straight side 206 b anda somewhat rounded side 207 b. This would enhance scoring upon expansionas the foreshortening of the braid would cause there to be forward forceon abrupt side 206 b, and hence scoring of the plaque. Upon contractionof the braid for removal, the somewhat rounded side would more easily beremoved from the fissure or scoring tract without tearing the plaque ortissue. FIG. 26C shows a scoring member 200 c with a slightly roundedapex 205 c and slightly rounded sides 207 c. There may be any number ofvariations that may be used to enhance scoring on one hand and todiminish the damage to the plaque or vessel wall upon collapsing orremoving the device on the other hand.

Along these same lines, returning to FIG. 25, another means of enhancingthe scoring while limiting the effects of the scoring element on thetissues when contracting or removing the apparatus because of the shearforces caused by the longitudinal movement of the braid may be to heatset at least some of the crossing support members 201 in an “open”position so that they are more or less self expanding. They would beheld in a contracted or compressed state by the other non crossingmembers 202 and the scoring members 200 but also by the proximaltraction on the outer sheath 144 of the device. When the balloon isexpanded, the braid may expand and the crossing members may bepositioned as in FIG. 25 as the pressure from the balloon would drivethe scoring members 200 into the plaque and overcome the tendency of thecrossing members 201 expand enough to compete with the scoring members200. When the balloon is relaxed to allow flow while the scaffold isstill expanded against the wall, the forward pressure on the outersheath of the device can keep the scaffold fully expanded and in thesame configuration as FIG. 25. However, when the forward pressure on theouter sheath is relaxed, the crossing members may tend to remainexpanded as they have been heat set in the open position. The scoringmembers of the braid may retract and the crossing members may movetoward the apex of the scoring members as the braid contracts furtheressentially shielding the apex of the scoring members from thesurrounding plaque and tissue, hence limiting and tearing of the plaqueand tissue by the scoring member. This action of outward pressure of thecrossing members 201 while the scoring members are contracting may urgethe tissue within the notches to be expressed from the notches, at leastbefore the entire braid is put into severe tension by traction of theouter sheath relative to the inner sheath. The crossing members 201 ofFIG. 25 also are beneath the scoring members 200 as well as within thenotches 203. Hence there may be some competition from this position tokeep the scoring members from relaxing properly and to inhibit theaction described in this paragraph. The crossing members however may noteffect or have minimal effect on the position of the scoring memberswhich has much more mass. Within the notches, they would only maintaintheir position while the scoring members retract. Most of the members ofthe braid are flat, hence the shear forces caused collapsing the braidand the resulting longitudinal movement of the braid will be minimizedby these non scoring support members that will compress the tissuerather than score it. Hence the overall design of the device with thevast majority of the members being of a flat atraumatic design mayprotect the plaque and tissues from the shear forces created fromcollapsing and removing the braid.

In the case of a non braided scaffold, including a laser cut scaffold,some of the struts of the scaffold may be constructed so that while mostall of struts are more or less configured in a cylindrical orientationwhen the device is contracted or collapsed for insertion, that uponexpansion some part of the struts or some of the struts may be orientedmore or less perpendicular to the vessel wall. These more or lessperpendicular struts, or members of the stent, will act as a scoringelement when compressed into the plaque by the expansion of the balloonagainst the stent or just by the self expanding action of the stent inthe case of a self expanding stent. When contracted or compressed forremoval, these struts or parts of the struts may return to the more orless cylindrical shape. Other struts or parts of struts may beconsistently oriented in a conventional cylindrical pattern to providestrength to the scaffold.

Further embodiments of the present invention that combine the featuresof the system would be to utilize the proximal occluder as the deliveryvehicle for the self expanding temporary scoring scaffold. Instead of aseparate outer tube constraining the self expanding temporary scoringscaffold, it may be placed within the proximal occluder which wouldconstrain it before delivery. To deploy the self expanding temporaryscoring scaffold, the proximal occluder catheter may be placed justdistal to the lesion to be dilated or treated, and the inner catheterattached to the self expanding temporary scoring scaffold would be heldin place while the proximal occluder catheter is withdrawn albeit withthe occlusion portion of the device in a contracted or non occlusiveconfiguration. Once the lesion is covered by the self expandingtemporary scoring scaffold, the proximal and distal occluders may bedeployed, the agent injected, and the lesion dilated, preferably with aballoon. Subsequently, the self expanding temporary scaffold would beleft expanded and the balloon collapsed along with the proximal anddistal occluders to restore blood flow. After several minutes to hours,the self expanding temporary scaffold would be recovered into theproximal occluder or some other specific delivery/recovery device.

FIG. 27 A-E show cross sections of a blood vessel 210 with partiallyoccluding plaque 211 and a vessel lumen 300. FIG. 27A shows the bloodvessel 210 with the occluding plaque and the vessel lumen 300 alone.FIG. 27B demonstrates the non expanded balloon 212 and scaffold 213 maybe indistinguishable from each other as they are immediately adjacent toone another, catheter shaft 199 and with the scoring members 200 of thescaffold 213 within the existing lumen 300 of the vessel 210. Thisconfiguration may generally correspond to FIG. 16 which is alongitudinal section of a non expanded interventional balloon device102.

FIG. 27C demonstrates the balloon 212 and scaffold 213 partiallyexpanded which can cause the scoring members 200 to createmicrofractures 215 with the plaque 211. The drug or substance may bepresent during this expansion if a fluid drug is utilized with theproximal and distal occluders as discussed elsewhere. Alternatively orin combination, the drug or substance may be delivered via a drug coatedballoon 212 at this time if it is to be delivered in that manner.Usually delivery by a drug eluting or drug weeping balloon 212 will bedone before or subsequent to this action, if that modality is utilized,as the drug eluting balloon 212 may not have enough radial force todistend the lesion adequately in at least some cases.

Normally, expansion by an angioplasty balloon would produce uncontrolledand random dissections in the plaque. These microfractures produced bythe scoring elements 200 of the temporary scaffold 213 produce smallerfocal and controlled dissections of the plaque which may result in fewerflow limiting dissections that may demand the subsequent placement ofpermanent stents. Also, the supporting elements of the temporaryscaffold 213 will hold the compressed plaque and pieces of thecompressed plaque against the vessel wall and prevent parts of theplaque and other tissue from protruding into the lumen and producing aflow limiting dissection. Moreover, the microfractures serve as conduitsor crevasses for the drug or substance to access the vessel wall wheremay act upon the smooth muscle cells to cause the smooth muscle cells torelax and prevent the smooth muscle contraction that causes acuteelastic recoil. Action of the drug or substance on the smooth musclecells also may result in a significant decrease in restenosissubsequently as well. The controlled dissections and microfractures fromthis scoring aspect may cause less injury to the vessel wall which alsomay result in fewer incidences of recoil, flow limiting dissections, andrestenosis even without the drug or substance. The combination of themechanical features of the current invention and the pharmaceuticalcomponent are often complementary. The mechanical features may limit therecoil, dissections and restenosis without the drug, but addition of thedrug may improve the results even more.

FIG. 27D demonstrates the balloon 212 to be deflated after havingcompressed the plaque and the scaffold against the plaque 211 compressedand the microfractures 215 extending further into the plaque 211. Atthis point, the scaffold 213 can be left expanded preferably for atleast several minutes to support the dilatation of the plaque 211 and toprevent recoil and dissections. The arrows demonstrate the outwardpressure to support the plaque and prevent recoil or flaps fromdissections from obstructing or limiting flow.

The leaves of the balloon 212 are collapsed and the balloon 212 isrefolded after it has been deflated.

FIG. 27E demonstrates the balloon 212 and scaffold 213 to have beenremoved leaving the dilated plaque 211 compressed against the arterialwall 210. Elastic recoil which occurs quite frequently has beenprevented by the simultaneous administration of the drug or substancewhile supporting the compressed plaque and arterial wall with thetemporary scaffold. Flow limiting dissections may be avoided because ofthe support of the arterial wall by the temporary scaffold. The drug orsubstance that has been administered and may prevent, or significantlylessen, restenosis. Hence, there is often no need for a stent to be usedas the problems solved by stent placement may have been addressed by theuse of the devices and methods in accordance with many embodiments ofthe current invention.

Combining the elements of many embodiments, including the temporarystent to dilate the lesion at a lesser pressure with less injury to thewall and to be utilized to reduce or eliminate elastic recoil along withone or more of the other modalities, may reduce or eliminate the needfor the administration of a drug agent to inhibit restenosis. However,combining the drug administration with another modality listed above andthe temporary stent element may even further solve many of the short andlong term sequelae of vascular intervention, and may even furthereliminate the need for stenting or surgery in many cases. If thedilatation of the lesion was adequate because of the proven effect ofthe typically wire-like temporary stent exterior to the balloon beingable to dilate plaque more effectively than POBA, if the lesion was heldopen by the temporary stent while the drug acts upon the smooth musclecells and to relax them preventing elastic recoil, and another modalityfrom the list above, for example electroporation, was utilized toenhance the absorption of the drug and to act on the cells of thevascular wall independently to further inhibit restenosis, then all ofthe reasons to use conventional, non-temporary stents would be obviated.The problems that stents solve may be eliminated. There may be no reasonto use a stent in many cases, and this would benefit the patient and thehealthcare system. Stents are not only costly, but have long termnegative consequences, including in-stent restenosis, late stentthrombosis, and the need to be placed on expensive and potentiallydeleterious drugs for extended periods.

In the case of electroporation, and some of the other modalities, anelectrically conductive temporary stent may be use to transfer theenergy or electrical pulses to the vessel wall. FIG. 21 illustrates anelectroporation catheter assembly 100 a constructed to permit theapplication of electric current to the wall of blood vessel 132 tocreate transient pores in the cell membrane through which, for example,a drug may pass. Braid 142, acting as a temporary stent, is connected toan external power source 160 and a computer-based controller 162 bywires 164 within the wall of external actuator sleeve 144. Controller162 would be utilized to program the pulse duration, sequence,amplitude, voltage, amperage, and other parameters to deliver theprescribed energy or electrical pulses to the vessel wall through thetemporary stent. It may also be utilized to ascertain electricalimpedance or other feedback parameters so that the proper energyparameters may be programmed or prescribed. In this example actuator 126electrically connects distal occluder 124 to ground 166 therebygrounding the vessel wall. Alternatively or in combination, the energy,such as in the form of electrical pulses, may be delivered through aconfiguration other than the temporary stent. The electroporation may beused to facilitate the delivery of a drug, but also may be used alone tocreate the pores in the wall of the cell without the drug being present.The cell is then unable to recover from having these pores in the wall,and it eventually dies, in effect a type of accelerated apoptosis.Adding the additional modality to the system of occlusion elements, druginfusion, dilatation and temporary stenting described herein would addvery little incremental cost, but may be necessary to reduce therestenosis rate under the 10% rate expected from the above systemwithout the additional modality.

Paclitaxel acts on the cytoskeleton or microtubules within smooth musclecells by enhancing polymerization and causes the smooth muscle cells torelax. There are other cellular effects, certainly, but thedysfunctional microtubules are thought to be reason the smooth musclecell relaxes rather than contracts as a result to exposure to certaindrugs. The temporary stent created by braid 142 combined with paclitaxelshould provide enough time of prolonged distension of the vessel for thepaclitaxel to act upon the cytoskeleton and microtubules so that thesmooth muscle cells would not contract upon the removal of the temporarystent. Many embodiments of the present invention may take advantage ofpaclitaxel or other antiproliferative drug through the use of the braid142 (or other stent structure) acting as a temporary stent to providethis action of prolonged expansion, allowing the drug to act upon thecells so that they will not contract when the temporary stent isremoved. Without the prolonged expansion, the drug would likely not haveenough time to act upon the cellular components to cause the smoothmuscle cell to relax. The extra time provided by the expanded temporarystent while blood is flowing through the area along with the uptake andaction of the drug will likely result in diminished elastic recoil ofthe vessel, and better long term patency.

Many embodiments of the present invention also provide a method ofinfusing an antiproliferative drug or other agent that acts upon thesmooth muscle cells and structures within the arterial wall andprolonging the distension of the vessel with a balloon, a temporarystent or scaffolding, or other structure to reduce the incidence ofelastic recoil, restenosis, and/or other effects of the intervention.

In one example, the above method may entail placing the proximal anddistal occluders on each side of the lesion to create an isolatedregion, activating the proximal and distal occluders, injecting thedrug, performing the therapeutic angioplasty intervention with atemporary stent device as has been described leaving the temporary stentexpanded against the vessel wall, deflating the angioplasty balloon soblood flow could be restored subsequently, aspirating the drug alongwith other flowable material (or even removing it from the isolatedregion by releasing it downstream), deactivating the proximal and distaloccluders, and removing the distal occluder. This may restore flow inthe vessel, and the temporary stent would still maintain annularpressure against the vessel wall to prevent elastic recoil while thedrug, having been absorbed by the smooth muscle cells, can act upon themicrotubules of those smooth muscle cells to create a relaxation ofthese smooth muscle cells and prevent acute elastic recoil. In someembodiments, the drug or other agent may be allowed to contact thetarget site for a period of time, such as from 30 seconds to 20 minutes,before the therapeutic angioplasty intervention, or other pressureapplying step, is performed. In some embodiments, the angioplastyballoon, or other pressure applying apparatus, can be used to applypressure to the vessel wall from about one minute to five days. When theballoon is left in place for extended periods, it is usually in acollapsed state to permit blood flow around it. It is expanded only whennecessary, such as to expand the lesion during angioplasty and to expandthe temporary stent.

Alternatively, the above example may be modified so that instead of atemporary stent, a plain angioplasty balloon device, a stent, such as abare metal stent or a bioresorbable or biodegradable stent which isintended not to be removed, atherectomy, or other therapeutic device isutilized. Also, the deactivated proximal and distal occluders may beleft in place within the vessel while a pressure device is providingforce against the vessel wall, and removed when the pressure device isremoved. The temporary stent or other pressure device would typicallyremain in place for at least several minutes and at most for severalhours to days to prevent elastic recoil. If, for example, the balloonassembly 140 of FIG. 20 is left in place for several days, balloon 102is collapsed permit blood flow around it. In such a procedure heparin orsome other agent could also be administered.

Moreover, the temporary stent may be used with other modalities otherthan drugs, such as radiofrequency, electroporation, heat, atherectomy,gene therapy, cryotherapy, electrical currents, radiation,iontophoresis, other pharmacological agents and substances, and thelike.

Other variations of temporary stenting, can be used. For example, thebraid 142 may be contracted by guide wire(s) instead of the actuatorsleeve 144. The braid may be contracted by moving the distal part of thebraid more distally by using an engagement device instead of an actuatorsheath. In other words, if the distal aspect of the braid was engaged orattached to the distal aspect of the guide wire rather than fixed to thedistal aspect of the balloon catheter as described in the preferredembodiments, then moving the guide wire distally would collapse thebraid and moving the guide wire proximally would expand the braid, or atleast maintain expansive pressure upon the already expanded braid.

Aspects of the present invention differ significantly from the Ya patentdiscussed above in that no dissolving agent outflow bores are used, thefocus is not directed to dissolving a thrombus, and anyantiproliferative agent is injected before the intervention and ispresent during the therapeutic intervention, not removed before theintervention as in Ya. Any subsequent intervention or therapy(angioplasty, stent placement, and the like) are performed after theremoval of the dissolved thrombus in Ya. Moreover, the thrombusdissolving agent and the dissolved thrombus must be removed in themethod of Ya, which is aimed at removing a thrombus, whereas there istypically no need to remove any antiproliferative agent when practicingthe present invention. The dose of the antiproliferative agent is muchlower than the systemic dose administered a patient receivingchemotherapy for treatment of a tumor.

In most embodiments disclosed in the Zadno-Azizi reference discussedabove, the device is comprised of two distinct lumens, an irrigationpathway and an aspiration pathway, much different from the device andmethod of the current invention. In the single example disclosed inZadno-Azizi in which there is only a single aspiration path, the therapycatheter must be removed for the device to function. In contrast withmany embodiments of the present invention, it is preferable to leave thetherapy device in place even if the injected substance is to be removed.In many cases, there is no need to remove any antiproliferative agentused with the present invention, again a distinction from the method ofZadno-Azizi. The fluid containing the embolic material must be withdrawnfor the Zadno-Azizi to be effective less the embolic material embolizesdownstream. The success of the many embodiments of the present inventionis not predicated on removal of any injected drug, as the drug may bereleased downstream where it likely would be harmless to the tissues.

Even more important in distinguising from the method of Zadno-Azizi isthe timing aspect. The fluid injected and aspirated is done after thetherapeutic invention with the Zadno-Azizi method whereas in accordancewith many embodiments of the present invention an agent to inhibitrestenosis, such as, but not limited to paclitaxel, is used—the agentmay be injected before the therapeutic procedure and left in placeduring the therapeutic procedure. The antiproliferative agent may or maynot be aspirated subsequent to the therapeutic procedure.

Moreover, the prior art devices of Ya and Zadno-Azizi both use a distaloccluder with a hollow lumen, which is needed to inflate the distalballoon. Many embodiments of the present invention have no need for thisfeature when the distal occluder is a mechanical blocking element sothat they are in no need for a hollow lumen along the distal occluder.

The balloon stent assembly according to many embodiments of the presentinvention, in contrast with known the temporary stents, will both dilatethe plaque in a controlled manner using the balloon, which causes littleinjury to the vessel, and supports the vessel for an extended period oftime using the temporary stent. Known temporary stents are commonlyintended to only support the vessel after something untoward happensduring the procedure, i.e., dissection, vasospasm, or vasoconstriction.Many embodiments of the present invention, because all of the functions(dilatation and support functions) happen more or less simultaneously,prevents noticeable dissections, vasospasm, or vasoconstriction as thevessel wall is supported during and immediately after the intervention,a great improvement over the prior art device. There is often virtuallyno time for the untoward events to occur with the current invention asthere is no time that the vessel wall does not have radial force beingexerted upon it. Moreover, many embodiments of the present inventionwill prevent acute elastic recoil which may be due to many other factorsother than dissection, vasospasm, or vasoconstriction.

In the case of an iatrogenically caused dissection from POBA, guide wirepassage, atherectomy, or instrumentation of any of many kinds, thetemporary stent may be used to “tack down” the flap from the dissection,and to improve the appearance of the vessel by expanding the temporarystent against the vessel wall, deflating the balloon and leaving thetemporary stent expanded for several minutes to an hour or so, whileproviding for blood flow through the area of interest.

In the case of spontaneous dissections, as in the aorta, the temporarystent may be utilized as a temporizing measure to direct blood flow intothe true lumen while the interventionalist is deciding on whichparticular stent graft to use and preparing for the insertion of a stentgraft. As well, in cases of aortic aneurismal rupture, the temporarystent may be used before the definitive treatment to stop the hemorrhageand stabilize the patient. In these cases, the temporary stent may ormay not have an elastomer or other material covering the part thatcontacts the vessel wall.

The above descriptions may have used terms above, below, top, bottom,over, under, et cetera. These terms may be used in the description andclaims to aid understanding of the invention and not used in a limitingsense.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention. It is intended thatthe following claims define the scope of the invention and that methodsand structures within the scope of these claims and their equivalents becovered thereby.

1.-19. (canceled)
 20. A method for treating a target site in a bodylumen, the method comprising: advancing a medical device to a targetsite in a body lumen, the medical device comprising an outer sheath, aninner sheath disposed coaxially within the outer sheath, an expandableelement attached to a distal end of the inner sheath, and a stent-likestructure mounted coaxially over the expandable element; expanding theexpandable element, thereby expanding the stent-like structure from acollapsed configuration to an expanded configuration, for a first periodof time; collapsing the expandable element after the first period oftime; maintaining the stent-like structure in the expanded configurationfor a second period of time after collapsing the expandable element,wherein the second period of time is longer than the first period oftime; collapsing the stent-like structure from the expandedconfiguration to the collapsed configuration after the second period oftime; removing the expandable element from the body lumen; and removingthe stent-like structure from the body lumen.
 21. The method of claim20, wherein the stent-like structure comprises a tubular mesh braid. 22.The method of claim 20, wherein the stent-like structure comprises alaser-cut stent.
 23. The method of claim 20, wherein collapsing thestent-like structure comprises moving the inner sheath relative to theouter sheath, thereby longitudinally lengthening the stent-likestructure.
 24. The method of claim 20, wherein a distal end of the ofthe outer sheath is coupled to a proximal end of the stent-likestructure and the distal end of the inner sheath is coupled to a distalend of the stent-like structure.
 25. The method of claim 20, whereinmaintaining the stent-like structure in the expanded configurationcomprises locking a position of the inner sheath relative to the outersheath.
 26. The method of claim 20, wherein expanding the expandableelement expands the stent-like structure into the expanded configurationagainst a wall of the body lumen.
 27. The method of claim 26, whereinmaintaining the stent-like structure in the expanded configurationcomprises maintaining the stent-like structure in the expandedconfiguration against the wall of the body lumen, thereby allowing fluidto move through the stent-like structure during the second period oftime.
 28. The method of claim 20, wherein the expandable elementcomprises a balloon and wherein expanding the expandable elementcomprises inflating the balloon.
 29. The method of claim 20, furthercomprising delivering, with the expandable element or the stent-likestructure or both, an agent directed to relaxing the body lumen orpreventing restenosis or both.
 30. The method of claim 29, wherein theagent comprises an anti-proliferative agent.
 31. The method of claim 20,wherein removing the expandable element from the body lumen and removingthe stent-like structure from the body lumen occur at the same time. 32.The method of claim 20, further comprising scoring a lesion or anocclusion in the body lumen with the stent-like structure while thestent-like structure is expanding or when the stent-like structure is inthe expanded configuration, wherein the stent-like structure comprises aplurality of scoring elements and a plurality of non-scoring elementsinterconnected with one another, and wherein the plurality ofnon-scoring elements are configured to radially support the body lumenwhen the stent-like structure is in the expanded configuration.
 33. Themethod of claim 31, wherein one or more of the plurality of scoringelements or the plurality of non-scoring elements are non-axial.
 34. Themethod of claim 32, wherein one or more of the plurality of scoringelements of the plurality of non-scoring elements are helically woundover a longitudinal axis of the stent-like structure.
 35. The method ofclaim 33, wherein one or more of the plurality of scoring elements orthe plurality of non-scoring elements are helically wound in the samedirection.
 36. The method of claim 31, wherein a cross-section of eachscoring element has one or more of a rounded, pointed, triangular, orrectangular shape.
 37. The method of claim 31, wherein a cross-sectionof each non-scoring element has one or more of a flat, rounded,rectangular, or cylindrical shape.
 38. The method of claim 20, whereinthe body lumen is a vessel and wherein treating the target sitecomprises one or more of diminishing elastic recoil, limiting dissectionor damage to a wall of the vessel, limiting vascular spasm, limiting oreliminating intramural hematoma, limiting restenosis, providing plaquecompression, or providing lumen gain.
 39. The method of claim 20,wherein collapsing the stent-like structure further collapses theexpandable element.
 40. The method of claim 20, wherein the target sitecomprises a plaque and wherein maintaining the stent-like structure inthe expanded configuration compresses the plaque and holds the plaqueagainst a wall of the body lumen.